Rotor valves are known for use in applications where a source of fluid is directed through a housing to one of several destinations. Such valves can be found in thermal management systems for automotive applications including engine cooling, vehicle cabin HVAC systems, emissions system valves, engine intake valves, engine exhaust management valves. A typical rotor valve has a rotor that can be rotated about a longitudinal axis in a chamber of a valve body or housing. When the rotor is rotated to a closed position, the rotor blocks fluid flow through a bore or passage in the housing. One problem with this type of valve is how to establish an effective fluid seal between the surface of the rotor and the valve body, while at the same time avoiding excessive operating torque or the need to have actuators of significant size. A rotor valve arrangement must both prevent fluid from exiting the valve housing when a particular inlet is in the closed position, but must also prevent pressurized fluid from entering the valve housing through a closed opening. Thus the operating conditions at the various interfaces between the rotor and inlets can vary since some of the bores may be pressurized or in a vacuum or at ambient pressures.
It is therefore desirable to have a new arrangement where the amount of friction between a resilient member of a piston and valve bore is reduced so that the force of the resilient member and actuator is used more efficiently and in some cases can be changed or reduced in size. It is also desirable to provide an improved arrangement where there is a better sealing connection between the seal arrangement and bore so that when the valve is in the closed position, there is no leakage.